Boynton :
This is certainly very interesting, and I had not heard of vocabularies this
large in non-human species.
On brain size, I know of the fallacy of strictly correlating "intelligence"
and brain size. However, I don't think there is no relationship between
brain size and "thinking" at certain levels of discrepancy in size , as
between humans and chimps. My thought is that the difference would have to
do with the extent to which symbolic thinking infuses all aspects of living
and activity. There may also be some difference in facility. ( Chomsky's
famous assertions on facility of language acquisition for human children is
to this point) To use Paul Dillon's analogy on tools concerning human
_dependence_ on tools, humans depend more fully and totally depend on
symbols than other species, maybe.
Part of this is a sort of circular argument. Why else did the brain size
grow from homo erectus to homo sapiens ? Rudimentary use of symbols grew
to comprehensive use. As there were mutations for increased brain size,
those with bigger brains expanded the use of the rudimentary symbol systems
to more comprehensive usagae, and this more comprehensive use of symbols was
an advantage, and selected for.
However, the difference in size within the human "range" does not make a
difference on this issue. It is only the difference between the human range
and the non-human range of sizes, if you follow.
Charles
^^^^^
Hello: This is a comment on the conversation between
Paul Dillon and Charles Brown on 'symboling', human
evolution, and brain size.
Communicating with symbols - sound, visual, or other -
is not limited to human beings, and is not so directly
related to brain size as people often suppose. Many
birds and many mammals communicate to each other with
sound symbols.
Science is only now unraveling the complexity of the
'speech and language' of other species. Some birds
with brains much smaller than ours - African Gray
Parrots for example - are able to develop large
vocabularies of human words and communicate their own
ideas (rather than mimicking human speech).
Chimpanzees, whales, porpoises, elephants and even
groundhogs each have their own kind of sound
communication system all of which include the
equivalent of words.
In the case of the African Gray parrots which speak
English and have been studied (the two most famous are
'Alex and N'kisi - Alex is currently at Brandeis
University) the birds clearly form sentences of
several words with grammatical rules, initiate
conversations with original thoughts, respond to
questions with uncoached answers, and even make jokes.
Alex is said to have a vocabulary of 950 words in
English (How many 'words' he has in his 'parrot'
vocabulary has not been reported on as far as I know.)
The implication of this information is that not just
brain size, but brain structure, is almost certainly
involved in the ability to learn speech, and in the
ability to develop abstract thought. The most recent
article I have read about Alex is about his ability to
use the concept 'none' - arguably a more abstract
concept than whole numbers like 'one', 'two' 'three'.
(Interestingly, Parrots - and maybe the other
'speaking species' besides humans - do not have
"Brokaws Area" (an area of the human brain long
recognized to play an important, but not clearly
understood, role in human speech.)
Of course, we do not need to look at animal speech to
guess that brain size is not the one and only
determining element in the abilities to speak, use
symbols, and think abstractly. Just consider the fact
that women usually have smaller heads and brains than
men, and then ask yourself how much brain size has to
do with intelligence. Or simply ask a woman.
The idea that the acquisition of the ability to speak
was a very important step in human evolution, and
probably in the evolution of the structure of the
brain, makes a lot of sense. Complex human societies
would be impossible without this ability, in fact
without the ability to record speech in writing or
some other visual equivalent of language,
'civilization' (as we call it) almost certainly could
not have evolved passed the stage of small towns and
villages.
What has not been established yet is how and when
humans acquired speech - nor how human speech evolved
before writing was developed. We probably never will
know the full story, even if archeology, paleontology,
DNA and language regressions, studies of human brain
structure and function - and what have you -advance
way beyond where they are now.
All the best, Anthony